Science Olympiad Previous Year Paper - 1 | Science Olympiad Class 7 PDF Download

Ans: (a)

Step 2:Split LATEST into two halves:

• First half: LAT
• Second half: EST

Step 3: Reverse LAT (first half) to get TAL.

• Add +2 to each letter in TAL:
• T → V (20 + 2 = 22, V)
• A → C (1 + 2 = 3, C)
• L → N (12 + 2 = 14, N)
• This gives VCN, which forms the second half of the encoded word.

Step 4: Reverse EST (second half) to get TSE.

• Add +2 to each letter in TSE:
• E → G (5 + 2 = 7, G)
• S → U (19 + 2 = 21, U)
• T → V (20 + 2 = 22, V)
• This gives VUG, which forms the first half of the encoded word.

Thus, LATEST → VUGVCN.

Using the same logic, 'SOURCE' will be coded as  'GETWQU'.

Ans: (d)

In the given word PROFESSOR, the following pattern is used:

P – 1 = O

R + 1 = S

O – 1 = N

F + 1 = G

E – 1 = D

S + 1 = T

S – 1 = R

O + 1 = P

R – 1 = Q

Similarly, ALLOWED will be coded as follows:

A – 1 = Z

L + 1 = M

L – 1 = K

O + 1 = P

W – 1 = V

E + 1 = F

D – 1 = C

Ans: (a)

The given pattern is made up of two series:

(i) E, F, G, ?

(ii) M, L, K, ?

Now, in the first series, the pattern is to add 1.

So, E + 1 = F

F + 1 = G

G + 1 = H

In the second series, the pattern is to subtract 1.

So, M - 1 = L

L - 1 = K

K - 1 = J

Therefore, the missing terms are H and J.

Ans: (d)

The series is as follows:

1 + 1² = 2

2 + 2² = 6

6 + 3² = 15

15 + 4² = 31

31 + 5² = 56

Ans: (b)

In this series, each number is repeated, then 13 is subtracted to arrive at the next number.

So, 27 - 13 = 14

Ans: (a)

• Isha is the daughter of Puneet.
• Suman is the sister of Puneet, making her the aunt of Isha.
• Since Isha is the daughter of Puneet, she is also the niece of Suman.
• Thus, the correct relationship is that Isha is Suman's niece.

Ans: (c)

According to the question,

6 × 8 = 48

And 48 – 1 = 47

Similarly, 8 × 8 = 64

And 64 – 1 = 63

Ans: (c)

• Sameer starts by running 80 m North.
• He then turns right (which is East) and runs 40 m.
• After another right turn (now facing South), he runs 20 m.
• Finally, he turns left (now facing East) and runs 40 m.
• To find the distance from the starting point, we can visualize his path: he ends up 100 m away from the starting point.

Ans: (b)

According to the question,

ACE : IKM

The pattern followed is as follows:

A + 8 = I

C + 8 = K

E + 8 = M

Now, out of the given options, the same rule is applied for option 2 as follows:

R + 8 = Z

T + 8 = B

V + 8 = D

Ans: (b)

A, B and C are siblings.

B is the nephew of D, so it means B is a male.

So, B is the brother of C.

Ans: (b)

As the pressure decreases, the air from high pressure area moves toward the low pressure area, hence the speed of wind increases. 

Ans: (d)

Holes are made in hanging banners and hoardings in order to tackle the air pressure. The air gets passed through these holes made on the hoardings or banners and thus, reduces the pressure of air on them. Therefore, the hoardings do not get blown away or tear due to air pressure. 

Ans: (a)

A convex lens is used as a magnifying glass. The convex lens bends the parallel rays so that they converge and create a virtual image on our eyes retinas. That virtual image on our retinas appears larger than the real object due to principles of geometry. 

Ans: (d)

Boiling water is an example of a physical change and not a chemical change because water vapour still has the same molecular structure as liquid water (H₂O). Since only the state of the substance has changed and not its chemical nature, it is a physical change.
However, electrolysis of water is a chemical change as the following reaction takes place:
2H₂O → 2H₂ + O₂
Burning of wood and rotting of garbage are also chemical changes as the chemical composition of the substance changes.

Ans: (a)

Camels have thick fur. Camel excrete very small amount of urine and dry dung which help it to conserve water. There's no evidence, though, that camels can store water for long periods of time anywhere in their bodies. Camels store fat in their humps, not water. They can very efficiently conserve water but not store it. Rather than directly storing water, camels are built for adapting to the scarcity of water.  

Ans: (c)
Neem leaves act as insecticides during storage. It protects the stored grains from insects and pathogens like fungi.

Ans: (b)
As sterilisation is obtained through heat treatment, similarly immunisation is obtained through vaccination.

Ans: (d)
When few pieces of chalk are mixed with water,  no new substance is not formed. So, it is a physical change. 

Ans: (c)
The kicking of a ball by the player is an example of a physical change.

Ans: (c)
The solutions which do not change their colour to either red or blue litmus are known as neutral solutions.

Ans: (d)
Nylon is used to make ropes because it is very strong. 

Ans: (d)
Synthetic fibres soak less water than natural fibres.

Ans: (b)
Nylon shrinks after exposure to flame, forms hard beads and gives a smell of burning hair. Wool burns slowly with a smell of burning hair. Acrylic burns with sooty flame, fabric shrinks and black beads are formed. Rayon burns quickly with a smell of burning paper.

Ans: (b)
Sodium and potassium are soft metals and can be easily cut with a knife.

Ans: (d)
Ions can have negative and positive chargers.

Ans: (a)
In oil wells, the layers containing petroleum oil and gas are above that of water, because oil and gas are lighter than water and do not mix with it.  Hence, X is natural is natural gas, Y is oil and Z is water. 

Ans: (d)

• Substance X turned phenolphthalein pink, indicating it is a base. Lime water is a common base.
• Substance Y turned the China rose indicator green, which suggests it is also a base. Milk of magnesia is known to have this effect.
• Substance Z turned methyl orange red, indicating it is an acid. Curd is acidic in nature.
• Thus, the correct identification of X, Y, and Z is Lime water, Milk of magnesia, and Curd, respectively.

Ans: (d)

When winds flow from land to ocean, they are called land breeze. During night, the land cools down faster than the ocean surface. The warmer air from the ocean surface rises up and creates an area of low pressure near the surface. This is filled in by cooler air from the land. This gives rise to the land breeze.  

Ans: (a)

During intense exercise, there may not be enough oxygen available to complete the process, so a substance called lactate is made. Our body can convert this lactate to energy without using oxygen.

Ans: (c)
Option (a) and (d) show fungi, while option (b) represents the picture of an Amoeba.

Ans: (b)
The shown microorganism is Spirogyra belonging to Algae. Spirogyra is a filamentous alga that consists of thin unbranched chains of cylindrical cells.

Ans: (d)
P is Amoeba, Q is Paramecium, R is Euglena, S is AIDS virus. In Amoeba, pseudopodia help in catching prey. In Paramecium, cilia help in locomotion.

Ans: (a)
The correct matching is

Ans: (c)

• The term ureotelic refers to organisms that excrete urea as their primary nitrogenous waste.
• In this case, the question asks for the count of such organisms among the given options.
• After analyzing the organisms, it is determined that 3 of them are ureotelic.
• This means that they primarily convert ammonia into urea, which is less toxic and easier to excrete.

Ans: (c)

• Anaerobic respiration occurs when there is no oxygen available.
• During this process, less energy is produced compared to aerobic respiration.
• In anaerobic respiration, food is typically broken down into carbon dioxide and alcohol, not just carbon dioxide and water.
• Organisms like yeast and certain bacteria utilize this method to generate energy.

Ans: (a)

The breathing is controlled by the movement of diaphragm. Diaphragm is a membrane which is between the chest and abdomen. The movement of diaphragm is controlled by a group of muscles, called intercostal muscles.

When the diaphragm moves down, the rib cage expands. This leads to the expansion inside the lungs. As a result, the air moves into the lungs. This process is called inspiration or inhalation.

Ans: (d)

Soil erosion is a naturally occurring process that affects all land forms. In agriculture, soil erosion refers to the wearing away of a field's topsoil by the natural physical forces of water and wind or through forces associated with farming activities such as tillage. Less use of fertilisers, planting grass and shrubs, and step farming all are the ways of preventing the soil erosion.

Ans: (b)

Crushing of a can only changes the shape of the object and is a physical change.

Since no new substance is produced, it cannot be a chemical change.

Ans: (a)

Water conservation includes all the policies, strategies and activities made to sustainably manage the natural resource fresh water, to protect the water environment, and to meet the current and future human demand. Generation of hydro electricity is a measure of making electricity by running water, it has nothing to do with water conservation.

Ans: (a)

• Roots of sweet potato play a crucial role in the plant's survival.
• They store food for the plant, which is essential for growth.
• Additionally, they absorb water and mineral salts from the soil, which are vital for the plant's health.
• While roots do transport nutrients, they do not only send them to the leaves, making option (a) the correct choice.

Ans: (c)
Plants and animal depend on each other to maintain the ecological balance. Plants not only depend on animals for their supply of carbon dioxide but also for other processes like pollination and dispersal of seeds.

Ans: (a)
Though mercury is closer to the sun than Venus, Venus is hotter than Mercury. The reason is that Mercury has no atmosphere and Venus has a thick atmosphere which can retain the heat.

Ans: (d)

• Stomata are small openings on leaves that allow gas exchange. In submerged aquatic plants, they are typically found on both sides of the leaves to maximize oxygen intake.
• A flexible stem helps the plant withstand water currents.
• Long and narrow leaves reduce resistance in water, aiding in movement and light capture.
• Absorbing dissolved oxygen through the body surface is essential for survival underwater.

Ans: (d)

• Pollination by air is known as anemophily, where pollen is carried by wind.
• Plants that rely on air for pollination typically have lightweight pollen and are often found in open areas.
• Options (iii), (iv), (v), and (vi) are examples of such plants that utilize wind for their reproductive process.
• Understanding the characteristics of these plants helps in identifying their pollination methods.

Ans: (a)

• S is described as containing one or more R, where the female gamete develops. This indicates that S plays a crucial role in reproduction.
• Option (b) is incorrect because it mentions pollen transfer to R of different flowers, which is not the case.
• Option (c) incorrectly states that Q has double layered pollen grains, while the key indicates otherwise.
• Option (d) changes the connection from stigma to S to stigma to T, which is not accurate.

Ans: (d)

• Amino acids are the building blocks of proteins, while fatty acids are components of fats. The statement suggests that the term "amino acids" is incorrect in the context and should be replaced with "fatty acids".
• The other options either suggest incorrect replacements or state that the term is already correct, which is not the case here.
• Understanding the difference between these terms is crucial in biology, as they play different roles in the body.
• Thus, the correct choice is to replace "amino acids" with "fatty acids".

Ans: (a)
In test tube P, iron nails do not rust because boiled water does not contain any oxygen. 

A thin layer of oil also prevents oxygen from reaching the water in the test tube. In test tube Q, iron nails do not rust because soda lime absorbs water vapours. In test tube R, iron nails will rust because water and oxygen both are available.

Ans: (a)
P is Rhizopus, Q is Giardia, R is Euglena and S is Volvox. Euglena (R) is considered as connecting link between plants and animals, Euglena (R) and Volvox (S) are parasites which live in the bodies of other organisms including human beings, and Volvox (S) is fungi.

Ans: (a)
The substance “X” burned in step 1 was magnesium. When magnesium ribbon is burnt in air, magnesium reacts with the oxygen present in the air to form magnesium oxide. Ash from magnesium ribbon is magnesium oxide. When this oxide is dissolved in water, it liberates hydroxyl ions in water. This makes the solution basic. Hence, we know in the basic solution red litmus turns into blue.